Nontarnishing detergent compositions containing water-soluble inorganic columbates



NON TARNISHING DETERGENT COMPOSITIONS CONTAINING WATER-SOLUBLE INORGANIC COLUMBATES Edgar E. Ruff, Bergenfield, and Elwin E. Smith, Paramus, N. J., assignors to Lever Brothers Company, New York, N. Y., a corporation of Maine No Drawing. Application June 28, 1956 Serial No. 594,354

12 Claims. (Cl. 252-435) This invention relates to detergent compositions containing tarnish inhibitors and more particularly to polyphosphate compositions containing water-soluble inorganic columbates as tarnish inhibitors.

Compositions widely used for detergent and other purposes. Aqueous solutions of polyphosphates tend, when at certain pH values, to tarnish German silver (a nickel-zinc-copper alloy) to a variety of shades from yellow to bluish-black, especially if the solutions are at elevated temperatures and are allowed to remain in contact with the alloy for several minutes. Since German silver is frequently used for household articles commonly washed in polyphosphate-built detergent compositions, it is evident that this is a serious problem.

In accordance with the instant invention polyphosphate compositions are provided containing a tarnish inhibitor which compositions inhibit the formation of tarnish upon German silver. The tarnish inhibitors of the invention are water-soluble inorganic columbates, for

example, sodium columbate and potassium columbate.

An amount of the water-soluble inorganic columbate is added to the polyphosphate composition which is suffi-. cient to give tarnish inhibition when the. composition is used in itsnormal way. It will be understood that the.

amount required will depend in part upon the tarnish in hibiting' properties of the particular columbate'in ques, tion, upon the tendency of the polyphosphate with which it is used to tarnish German silver, and upon the amount of polyphosphate present. In general, therefore, at least about 0.6%, and preferably at least about 2%, of the water-soluble inorganic columbate based on the weight of the polyphosphate present in the detergent composition will inhibit the formation of tarnish by the composition.

The ,maximumamount of the columbate is not critical, but more than is necessary to give the desired effect will pH values'where such polyphosphates tend to tarnish German silver, i. e., usually within the rangeof about pH 8 to; about pH 11. .The alkali'metal polyphosphates containing polyphosphates are now present inventionare ef-. fe'ctivewith water-solublev alkali metal polyphosphates at.

2,829,105 Patented Apr. '1, 1958 2 organic nonsoap detergents which may be either anionic, cationic, or nonionic detergents and builders, water, and inert materials. These detergent compositions may include alkali metal polyphosphate in any amount, usually between'15% and conventional proportions of nonsoap detergent, usually within the range between 5% and 40%; from about 0.6%, and preferably from about 2%,

to about 15% of a water-soluble inorganic columbate based on the weight. of the polyphosphate; and the balance builders and inert materials.

The alkylaryl sulfonates are a class of anionic deter.-v gents which may be included in the detergent .compositions. One example thereof is the sulfonated phenyl polypropylene alkanes, characterized by the branched chain" structure of polypropylene and a tertiary alkyl carbonat the benzene ring, and having the following general structure:

HiRi v R1 7 sontt where M is hydrogen, an alkali metal or an organic amine cation, and R and R are alkyl, of the type formula.

C H and at least one R is a polypropylene group, the whole alkyl group containing preferably twelve to fifteen carbon atoms. These are known compounds whose preparation and properties are set forth'in'U. SJ

and R is an alkyl or alkylene radical, such as myristyl;

palmityl, oleyl, andstearyl. Sodium palmitic tauride, sodium palmitic methyl tauride, sodium myristic methyl tauride, sodium palmitic-stearic methyl tauride and -so-. dium palmitic methyl amidopropane sulfonate are-typical examples thereof.

These compounds are prepared by interacting the corresponding aliphatic acid anhydride or halide with an organic aliphatic aminosulfonic acid, ,such as taurine, NH CH CH SO H, and the various N-substituted taurines, such as N-methyl taurine, or aminopropane sulfonic acid, NH2(CH2)3SO3H.

Other water-soluble alkyl aromatic sulfonic acids may constitute optional components such as those preparedby:

' alkylating benzene or naphthalene with a kerosene fracmay include, by way of example, pentasodium and pentaa.

potassium. tripolyphosphates, tetrasodium and tetrapotassium pyrophosphates, sodium and potassium hexameta.

phosphates, and hexasodium and hexapotassium tetrapolyphosphates. There is no critical amount of alkali metal polyphosphate which need be employed in the corn-- included; in the 1 detergent; compositions.

nfixamples ofsuch additional optional components are nso ap detergents. and builders which-might be tion followed by sulfonation to aliphatic sulfonic acids,- esters. of sulfuric acid with aliphatic alcohols of ten to eighteen carbon atoms, particularly those derived by thereduction of coconut oil, palm oil, and like long-chain fatty acids, sulfonated castor oil, esters. and ethers 10f: isethionic acid, long-chain fatty acid esters and long-chain:

alkyl ethers of 2,3-dihydroxypropane sulfonic acidand sulfuric acid esters of monoglycerides and glycerol inono-.

I ethers. The salts of these acids are ordinarily employed;

The tarnish inhibitor s are also useful,withfnonionic.v detergents containing polyphosphates, such as, for ex-' ample alkyl oxyether and ester and thio'ether-and ester? detergents having the following general formula:

where R is a straight or branched chain saturated or unsaturated hydrocarbon group having from eight to eighteen carbon atoms or an aralkyl group having a straight or. branched chain saturated or unsaturated hydrocarbon group of from eight to eighteen carbon atoms attached to the aryl nucleus, and attached to A through the aryl nucleus, A is selected from the group consisting of ethereal oxygen and sulfur, carboxylic ester and thiocarboxylic ester groups and x is a number from eight to twenty. R can, for example, be a,straight or branched chain octyl, nonyl, decyl, lauryl, myristyl, cetyl, or stearyl group, or an alkylaryl group such as octylbenzene, nonylbenzene, decylbenzene, stearylbenzene, etc.

The sulfatedethoxynated derivatives of the above also L are useful anionic detergents:

where Mis hydrogen or an alkali metal or organic amine cation and x, A andR are as above.

When R is alkyl it will be evident that the detergent can be regarded as derived from an alcohol, mercaptan, oxy or thio fatty acid of high molecular weight, by condensation with ethylene oxide. Typical of this type of alkyl ether are the condensation products of oleyl or dodecyl alcohol or mercaptan with from 8 to 17 moles of ethylene oxide, such as Emulfor ON, Nonic 218 and Sterox SE and SK. Typical alkyl esters are 61226 and Renex '(polyoxyethylene ester of tall oil acids), Sterox CD" and Neutronyx 330 and 331 (higher fatty acid esters of polyethylene glycol).

Where. R is aralkyl, the detergent can be derived from an alkyl phenol or thiophenol.

The ethoxynated alkyl phenols and thiophenols have the following general formula:

where R is a straight or branched chain saturated or unsaturated hydrocarbon group having at least eight carbon atoms up to approximately eighteen carbon atoms, A is oxygen or sulfur and x is a number from eight to twenty. R can, for example, be a straight or branched chain octyl, nonyl, decyl, lauryl, cetyl, myristyl, or stearyl group. Typical are the condensation products of octyl and nonyl phenol and thiophenol with from 8 to 17 moles of ethylene oxide, available commercially under the trade names NIW, Antarox A-400," Igepal CA and CO," Triton X400, Neutronyx 600 and Tergitol NFX.

The optional supplemental builders may be alkali metal inorganic salts, typical examples of which include sodium and potassium sulfates, sodium and potassium chlorides,

sodium and potassium silicates, and sodium and potassium carbonates. In addition to or instead of the above mentioned supplemental inorganic salts, organic materials, such as sodium carboxymethylcellulose may be used as builders.

The builder mixture is so chosen among alkaline, neutral and acidic salts that the composition obtained in an aqueous 0.l4% washing solution has a pH of about 8 or above. Preferably its pHlies in the range of about 8 to about 11, since solutions which are more alkaline may be irritating to the skin and tend to weaken some fabrics, particularly woolens.

The detergentcornpositions of the invention inhibit the formation-of tarnish-upon German silver in either hard or soft water. It will be appreciated that the detergent compositions may exist in any dry form, such as drumdriedor spray-dried detergent compositions, or may be in liquid form. r

The polyphosphate detergent compositions may be prepared by conventional methods, as by blending the in- 4 gredients thereof in an aqueous solution or slurry and then drying the resulting mixture in a spray or drum dryer at elevated temperatures.

The tarnish inhibitors may be added to the polyphosphate composition in any stage of its manufacture, to the finished polyphosphate composition, or to the polyphosphate solution.

The compositions of the invention will be further illustrated by the following examples wherein a typical watersoluble inorganic columbate, namely potassium columbate, was employed in the compositions. The potassium columbate was tested as a solution of potassium columbate prepared by fusing 0.25 gram of columbium pentoxide with 2.0 grams of potassium carbonate, cooling the melt, and dissolving the resulting potassium columbate in 500 milliliters of water.

In these examples the following procedure was employed. Five grams of a polyphosphate composition (or an equivalent weight of a component thereof where specifled) was dissolved in 600 milliliters of water. One-tenth of this volume, or 60 milliliters, was placed in a 200 milliliter beaker and the required volume of inhibitor solution added. The volume of solution in the beaker was made up to milliliters. The final concentration of polyphos' phate composition or component is equivalent to five grams whole composition per quart of water. The pH at room temperature was adjusted to the desired level with sodium hydroxide or hydrochloric acid solutions. The solution was then heated to l60165 F., and placed in a water bath to maintain the temperature of the solution at -165 F. A German silver metal strip, one inch by six inches, cleaned with a Noxon metal polish, rinsed, and buffed with a cloth, was partially immersed in the solution and allowed to remain for one-half hour. At the end of that time, the strip was removed, rinsed, dried with a cloth, and visually examined for tarnish. The effectiveness of the tarnish inhibitor was rated as follows:

Degree of 'lnrntsli No tarnish.

Interface stain only.

Barely noticeable tarnish.

Slight tarnish.

Moderate tarnish.

Considerable (heavy) tarnish.

Severe, as when inhibitor is absent.

Examples l-4 below show that a water-soluble inorganic columbate inhibits the formation of tarnish by typical polyphosphates, such as pentasodium tripolyphosphate and tetrasodium pyrophosphate.

EXAMPLES 14 Percent Potassium Oolumbate (expressed as 001- lumbium Pentoxide) (polyphosphate basis) 0.0 2. 2 6. 7

Polyphosphate Tarnish Grade Tetrasodium Pyrophosphate (Examples 1-2) 6 2 Pentasodium Tripolyphosphate (Examples 3-4). 6 3

The addition of a water-soluble inorganic .columbate to polyphosphate compositions containing an organic nonsoap detergent, which may be either anionic, nonionic, or cationic, as well as builders inhibits the formation of tarnish by such detergent compositions. This is clearly illustrated by the examples set forth below wherein the eight compositions of Table I were employed.

Table] as tarnish inhibitors in polyphosphate compositions containing either an organic cationic non-soap detergent or Compositions Sodium Dodecylbenzene Sulfonate Laurie Ester of N-(beta-hydroxy-ethyD- alpha-(ehloropyridinium) acetamide [Emulsept] Pluronie Tetrasodium Pyrophosphate. Sodium Hexametaphosphate Hexasodium Tetrapolyphosnhato Sodium Silicate Sodium Carbonate Sodium Oarboxymethylcellulos Water Sodium Sulfate Total In Compositions A through H the amounts of the various components are expressed in percent by weight. Pluronic L-64 is an organic 'nonionic nonsoap detergent having the empirical formula Ito-(cam m t t nwzm nn prepared by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol where b is an integer selected from the group consisting of 26 to 30 and a plus is an integer such that the molecule contains from 40% to 50% of ethylene oxide.

Examples -14 show that at least about 0.6% of a water-soluble inorganic columbate based on the weight of polyphosphate inhibits the formation of tarnish by polyphosphate compositions containing an organic anionic nonsoap detergent and supplemental builders.'

EXAMPLES s-14 To five grams each of Compositions A and B there was added potassium columbate in the proportions shown below and the test procedure carried out with the following results. In Examples 58 the pH of the test solution was 8, while in Examples 9-14 the pH of the test solution was 10.

Percent Potassium Colunibate (expressed as Oolumbium Pentoxide) (polyphosphate basis) 0.0 0.6 1. 1 2. 2 4. 4 6. 7 Grading (Composition A) (Examples 5-8) 6 2 2 2 Grading (Composition B) I (Examples 9-14) 6 3 3 3 3 2 A water-soluble inorganic columbate is efiective as a tarnish inhibitor in polyphosphate compositions containing an organic nonsoap detergent as well as supplemental builders when the alkali metal polyphosphate is other than tetrasodium pyrophosphate or pentasodium tripolyphosphate, for example, sodium hexametaphosphate or hexasodium tetrapolyphosphate. This is clearly illustrated by Examples -18 set forth below.

EXAMPLES 15-18 Five grams each of Compositions G at pH 9 and H at composition upon German silver at pH 11 was reduced I to grade 1, indicating interface stain only.

Water-soluble inorganic columbates are also efiective 'pH 11 per quart of distilled water tested in'accordance an organic nonionic nonsoap detergent as well as supplemental builders, as illustrated by Examples 1926.

EXAMPLES 19-26 Five grams each of Compositions C and D (cationic detergents) and E and F (nonionic detergents) per quart of distilled water were tested in accordance with the test procedure. Compositions C and B were tested at pH 11, while Compositions D and F were tested at pH 8. All four of these compositions tarnished German silver to grade 6. When 6.7% of potassium columbate (expressed as columbium pentoxide) based on the weight of polyphosphate was added to each of these compositions, Composition C then had a reduced tarnish grading at the specified pH value of 1, while Compositions D, E, and F then had a reduced tarnish grading at the specified pH values of 2.

The amount of the alkali metal polyphosphate present in the polyphosphate compositions may be as low as about 15% as noted above and as further illustrated by Examples 27-28.

I EXAMPLES 27-28 15 of pentasodium tripolyphosphate was employed in Composition B with the amount of sodium sulfate being increased to offset the decrease in the pentasodium tripolyphosphate content of the composition (30% additional sodium sulfate). Five grams of this modified composition per quart of distilled water at pH 10 had a tarnish grading of 4 upon German silver metal, whereas five grams of the modified composition per quart of distilled water which also contained 6.7% of potasium columbate EXAMPLES 29-30 Five grams of Composition B per quart of water having a hardness of p. p. m. at pH 11 tarnished German silver to grade 5, whereas five grams of Composition B containing 6.7% of potassium columbate (expressed as columbium pentoxide) based on the weight of polyphosphate per quart of water having a hardness of 180 p. p. m. at pH 11 tarnished German. silver only to grade 1.

The effectiveness of water-soluble inorganic columbates as tarnish inhibitors with liquid polyphosphate detergent compositions is clearly illustrated in Examples 31- 32.

EXAMPLES 31-32 Two 11.25 gram portions of the following liquid detergent composition were dissolved separately in one quart. of distilled water and potassium columbate added to one at the concentration indicated below. The tarnish grading of a strip of German silver metal inserted in each of the solutions at pH 9 is also set forth. It will be noted that 11.25 grams of the liquid product provides the same amount of polyphosphate (2.25 grams) as the standard five grams of granulated detergent containing 45% polyphosphate.

Composition Percent by Weight Potassium Dodecylbenzene Sulionate 10.0 Sodium Xylene Sultanate.-. 7. 6 Laurie Isopropauolamide. 3. 2 Laurie Diethanolamlde. 3. 8 'letrapotassium Pyropho hate 20.0 Sodium Silicate 7.0 Water 48. 4

Total 100.

Example N o 31 32 Percent Potassium Columbate (expressed as Coluinbium Pentoxide) (polyphosplmte basis) 0.0 0.7 'lurnish Grade. 6 2

It should be borne in mind that this invention relates to tarnishing and tarnish inhibitors and does not pertain to alkaline corrosion or corrosion inhibitors. Tarnishing and corrosion of metals are two quite dissimilar phenomena. A discoloration is the principal manifestation of tarnishing, while a dissolving action characterizes corrosion ofmetal. Corrosion inhibitors are effective because they remove oxygen from the alkaline medium surrounding the metal being corroded. The antitarnishing action of a Water-soluble inorganic columbate on German silver, on the other hand, is due to a different mechanism, since the presence of oxygen is not necessary to the tarnishing action of polyphosphates on German silver.

Obviously many modifications and variations may be made in the invention herein set forth without departing from the spirit thereof, and only such limitations should be imposed as are indicated in the appended claims.

We claim: i

1. A detergent composition consisting essentially oi an alkali metal polyphosphate which in aqueous solution tarnishes German silver and a water-soluble inorganic columbate in an amount to lessen the tarnishing action of the polyphosphate.

2. A detergent composition consisting essentially of an alkali metal polyphosphate selected from the group consisting of alkali metal tripolyphosphates and pyio' phosphateswhich in aqueous solution tarnishes German silver and from about 2% to about 15% of a water soluble inorganic columbate to lessen the tarnishing action of the polyphosphate.

3. A detergent composition as set forth in claim 2 wherein the columbate is potassium columbate.

4. A detergent composition consisting essentially of from about 15% to about of an alkali metal polyphosphate which in aqueous solution tarnishes German silver, from about 5% to about 40% of an organic nonsoap detergent, and a water-soluble inorganic columbate in an amount from about 0.6% to about 15% based on the weight of the polyphosphate and suiiicient to inhibit such tarnishing.

5. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal tripolyphosphate.

6. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal pyrophosphate.

7. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal hexametaphosphate.

8.A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal tetrapolyphosphate.

9. A detergent composition as set forth in wherein'the organic nonsoap detergent is an cationic nonsoap detergent.

10. A detergent composition as set forth in claim 4 wherein the organic nonsoap detergent is an organic nonionic nonsoap detergent.

ll. A detergent composition as set forth in claim 4 wherein the organic nonsoap detergent is an organic anionic nonsoap detergent.

12. A detergent composition as set forth in wherein the columbate is potassium columbate.

claim 4 organic claim 4 References Cited in the file of this patent UNITED STATES PATENTS 2,303,399 Schwartz Dec. 1, 1942 2,419,805 Wegst Apr. 29, 1947 2,425,907 Wegst Aug. 19, 1947 2,618,604 Schaeffer Nov. 18, 1952 OTHER REFERENCES Smiths College Chemistry, William F. Ehret, 6th edition, 1946, Periodic Classification of the Elements on inside back cover. 

1. A DETERGENT COMPOSITION CONSISTENTLY ESSENTIALLY OF AN ALKALI METAL POLYPHOSPHATE WHICH IN AQUEOUS SOLUTION TARNISHES GERMAN SILVER AND A WATER-SOLUBLE INORGANIC COLUMBATE IN AN AMOUNT TO LESSEN THE TARNISHING ACTION OF THE POLYPHOSPHATE. 